Right now we use ManageEngine ServiceDesk, but are considering a switch to BaseCamp. Most people we know that use BC love it.
Our video guys use 2 20" Cinema Displays for our editing, and the designers work on iMacs. We work our Macs pretty hard, but keep each computer for at least three years (the length of warranty) before we consider upgrading. Usually it’s longer than that unless there’s a breakdown.

